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841.
Ming-Jung Wu Chi-Fong Lin Li-Juan Chang Pao-Tzu Jing Tsai-Hui Duh Wuan-Ting Tseng Fang-Chen Lee Shan-Shue Wang Hsueh-O Chang 《中国化学会会志》1998,45(6):783-788
A series of molecules containing monopropargyl sulfone or 1, 2-bis-propargyl sulfone were synthesized. The cytotoxicity of these compounds against human carcinoma cells was also examined. This study indicated that the formation of a biradical intermediate is important to the potency of cytotoxicity. 相似文献
842.
843.
844.
We consider the minimization problem with strictly convex, possibly nondifferentiable, separable cost and linear constraints.
The dual of this problem is an unconstrained minimization problem with differentiable cost which is well suited for solution
by parallel methods based on Gauss-Seidel relaxation. We show that these methods yield the optimal primal solution and, under
additional assumptions, an optimal dual solution. To do this it is necessary to extend the classical Gauss-Seidel convergence
results because the dual cost may not be strictly convex, and may have unbounded level sets.
Work supported by the National Science Foundation under grant NSF-ECS-3217668. 相似文献
845.
J. Y. Yang C. L. Tseng J. M. Lo M. H. Yang 《Fresenius' Journal of Analytical Chemistry》1985,321(2):141-145
Summary Lithium in environmental, biological and metal samples was determined by neutron activation analysis via the6Li(n,)T and16O(T,n)18F reactions. The samples were converted to aqueous solutions either by dissolution or by digestion and their aliquots were irradiated in a nuclear reactor for 2 h. The irradiated sample solution, was placed in a ZrO2 column on which the18F nuclide was adsorbed. Most of the coexisting nuclides24Na,82Br,38Cl,64Cu, etc. were separated by elution with pH 1 3 solution. The column was subjected to a Ge(Li) detector for-ray spectrometry. The lithium content in the sample was estimated from the18F activity obtained. The matrix effect can be eliminated by either strong dilution of the samples in aqueous medium or by the method of standard addition. Lithium can be determined with high precision and accuracy in sub-ppm samples.
Bestimmung von Lithiumspuren in biologischen, Umwelt- und Metallproben mit Hilfe der Neutronenaktivierungsanalyse
Zusammenfassung Lithium wird über die Reaktionen6Li(n,)T und16O(T,n)18F bestimmt. Die Proben werden durch Auflösung oder Aufschluß in wäßrige Lösung übergeführt und im Reaktor 2 h lang bestrahlt. Die bestrahlte Lösung wird auf eine ZrO2-Säule gegeben, wo die18F-Nuklide adsorbiert werden. Die meisten anderen Nuklide (24Na,82Br,38Cl,64Cu usw.) werden durch Elution mit Säurelösung pH 1 3 abgetrennt. Die-Spektrometrie erfolgt mit einem Ge(Li)-Detektor. Der Lithiumgehalt ergibt sich aus der18F-Aktivität. Durch starke Verdünnung oder durch das Standardzugabeverfahren kann der Matrixeffekt eliminiert werden. Lithium ist so mit hoher Präzision und Genauigkeit in sub-ppm-Proben bestimmbar.相似文献
846.
S. M. Lin C. H. Chiang C. H. Huang C. L. Tseng M. H. Yang 《Journal of Radioanalytical and Nuclear Chemistry》1985,96(2):153-160
Five kinds of urinary stones from 42 patients have been determined for a total of 19 elements by instrumental neutron activation analysis. Of these elements, Ca, Mg, Sr, Na, and Cl are found to be present in the core of all kinds of stones. The differences in elemental composition among the different kinds of stones as well as across the layers of stone are statistically evaluated. 相似文献
847.
Trischuk W de Troconiz JF Truitt S Tseng J Turini N Ukegawa F Valls J Vejcik S Velev G Vidal R Vilar R Vologouev I Vucinic D Wagner RG Wagner RL Wahl J Wallace NB Walsh AM Wang C Wang CH Wang MJ Watanabe T Waters D Watts T Webb R Wenzel H 《Physical review letters》2000,84(5):835-840
We present the results of a search for pair production of a fourth-generation charge -1 / 3 quark (b(')) in sqrt[s] = 1.8 TeV p&pmacr; collisions using 88 pb(-1) of data obtained with the Collider Detector at Fermilab. We assume that both quarks decay via the flavor-changing neutral current process b(')-->bZ(0) and that the b(') mass is greater than m(Z)+m(b). We studied the decay mode b(')b(');-->Z(0)Z(0)b&bmacr; where one Z0 decays into e(+)e(-) or &mgr;(+)&mgr;(-) and the other decays hadronically, giving a signature of two leptons plus jets. An upper limit on the sigma(p&pmacr;-->b(')b(');)x[B(b(')-->bZ(0))](2) is established as a function of the b(') mass. We exclude at 95% confidence level a b(') quark with mass between 100 and 199 GeV/c(2) for B(b(')-->bZ(0)) = 100%. 相似文献
848.
We revisit the phenomenon of quantum stochastic resonance in the regime of validity of the Bloch equations. We find that a stochastic resonance behavior in the steady-state response of the system is present whenever the noise-induced relaxation dynamics can be characterized via a single relaxation time scale. The picture is validated by a simple nuclear magnetic resonance experiment on water. 相似文献
849.
Theriot D Thurman-Keup R Tipton P Tkaczyk S Tollefson K Tollestrup A Toyoda H Trischuk W de Troconiz JF Tseng J Turini N Ukegawa F Vaiciulis T Valls J Vejcik S Velev G Vidal R Vilar R Volobouev I Vucinic D Wagner RG Wagner RL Wahl J Wallace NB Walsh AM Wang C 《Physical review letters》2000,85(16):3347-3352
This Letter describes a direct measurement of the W boson total decay width, gamma(W), using the Collider Detector at Fermilab. The measurement uses an integrated luminosity of 90 pb(-1), collected during the 1994-1995 run of the Fermilab Tevatron p&pmacr; collider. The width is determined by normalizing predicted signal and background distributions to 49 844 W-->enu candidates and 21 806 W-->&mgr;nu candidates in the transverse-mass region M(T)<200 GeV and then fitting the predicted shape to the 438 electron events and 196 muon events in the high- M(T) region, 100相似文献
850.
Hsu JP Ting CC Lee DJ Tseng S Chen CJ Su A 《Journal of colloid and interface science》2007,307(1):265-271
The electrokinetic flow of an electrolyte solution through a microchannel that comprises a bundle of cylinders is investigated for the case of constant surface potential. The system under consideration is simulated by a unit cell model, and analytical expressions for the flow field and the corresponding residence time distribution under various conditions are derived. These results are readily applicable to the assessment of the performance of a microreactor such as that which comprises a bundle of optical fibers. Numerical simulations are conducted to investigate the influences of the key parameters, including the thickness of the double layer, the strength of the applied electric field, the magnitude of the applied pressure gradient, and the characteristic sizes of a microchannel, on the residence time distribution. We show that the following could result in a shorter residence time: thin double layer, strong applied electric field, large applied pressure gradient, and small number of cylinders. Based on the thickness of the double layer, criteria are proposed for whether the flow field can be treated as a laminar flow or as a plug flow, two basic limiting cases in reactor design. 相似文献