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71.
The reactions of IO radicals with CH3SCH3, CH3SH, C2H4, and C3H6 have been studied using the discharge flow method with direct detection of IO radicals by mass spectrometry. The absolute rate constants obtained at 298 K are the following: IO + CH3SCH3 → products (1): k1 = (1.5 ± 0.2) × 10?14; IO + CH3SH → products (2): k2 = (6.6 ± 1.3) × 10?16; IO + C2H4 →products (3): k3 < 2 × 10?16; IO + C3H6 → products (4): k4 < 2 × 10?16 (units are cm3 molecule?1 s?1). CH3S(O)CH3 and HOI were found as products of reactions (1) and (2), respectively. The present lower value of k1 compared to our previous determination is discussed. 相似文献
72.
本文自行设计和制作了1.30μmDFB激光器组件的讨论了光隔离和光耦合原理。由于采用的激光器-光隔离器-光纤的一体化结构,大大增加了该组件的可用性。在实验中得到高达55%的耦合效率。 相似文献
73.
The International Telecommunication Union (ITU) has completed work on a series of standards on asynchronous transfer mode (ATM) equipment functional operations and network element management. The objective of these standards is to enable flexible design and interoperability of network elements for use in a global ATM network, independent of any specific implementation. This article discusses these standards with respect to their development and application in planning ATM networks. Specifically, it addresses the following: the modeling approach taken in the development of the ITU standards, key operational features specified in the ATM network element functional model, and the capabilities of the ATM network element management interface. Examples of ATM equipment are provided to illustrate how the functional models specified in the ITU standards may be used by network planners and equipment manufacturers to specify and develop ATM equipment tailored to specific needs, while ensuring network interoperability. The article concludes with some points on the future enhancement of these and related ATM equipment operations standards 相似文献
74.
S. Bouneau F. Azaiez J. Duprat I. Deloncle M.G. Porquet A. Astier M. Bergström C. Bourgeois L. Ducroux B.J.P. Gall M. Kaci Y. Le Coz M. Meyer E.S. Paul N. Redon M.A. Riley H. Sergolle J.F. Sharpey-Schafer J. Timar A.N. Wilson R. Wyss 《The European Physical Journal A - Hadrons and Nuclei》1998,2(3):245-248
75.
S. Franchoo F. Ibrahim F. Le Blanc M. Lebois A. Olivier C. Phan Viet B. Roussière R. Sifi D. Verney 《Hyperfine Interactions》2006,171(1-3):117-119
The availability of both a tandem deuteron beam and a linac electron beam, the latter converted into Bremsstrahlung, at the
new ALTO facility at IPN-Orsay offers a unique opportunity to compare the performance of a laser ion guide under different
regimes. The ALTO accelerator has delivered its first electron beam at the end of 2005 and a design for a gas-cell prototype
is being studied. 相似文献
76.
77.
78.
79.
K. Najim L. Pibouleau M. V. Le Lann 《Journal of Optimization Theory and Applications》1990,64(2):331-347
Optimization techniques are finding increasingly numerous applications in process design, in parallel to the increase of computer sophistication. The process synthesis problem can be stated as a largescale constrained optimization problem involving numerous local optima and presenting a nonlinear and nonconvex character. To solve this kind of problem, the classical optimization methods can lead to analytical and numerical difficulties. This paper describes the feasibility of an optimization technique based on learning systems which can take into consideration all the prior information concerning the process to be optimized and improve their behavior with time. This information generally occurs in a very complex analytical, empirical, or know-how form. Computer simulations related to chemical engineering problems (benzene chlorination, distillation sequence) and numerical examples are presented. The results illustrate both the performance and the implementation simplicity of this method.Nomenclature
c
i
penalty probability
-
cp
precision parameter on constraints
-
D
variation domain of the variablex
-
f(·)
objective function
-
g(·)
constraints
-
i,j
indexes
-
k
iteration number
-
N
number of actions
-
P
probability distribution vector
-
p
i
ith component of the vectorP as iterationk
-
r
number of reactors in the flowsheet
-
u(k)
discrete value or action chosen by the algorithm at iterationk
-
u
i
discrete value of the optimization variable in [u
min,u
max]
-
u
min
lowest value of the optimization variable
-
u
max
largest value of the optimization variable
-
Z
random number
-
x
variable for the criterion function
-
xp
precision parameter on criterion function
-
W(k)
performance index unit output at iterationk
-
0, 1
reinforcement scheme parameters
-
p
sum of the probability distribution vector components 相似文献
80.
J. -F. Le Gall 《Probability Theory and Related Fields》1988,78(3):389-402
Summary We consider the following heat conduction problem. Let K be a compact set in Euclidean space 3. Suppose that K is held at the temperature 1, while the surrounding medium is at the temperature 0 at time 0. Following Spitzer we investigate the asymptotic behaviour of the integral E
K
(t) which represents the total energy flow in time t from the set K to the surrounding medium 3–K. An asymptotic expansion is given for E
K
(t) which refines a theorem due to Spitzer. This expansion also verifies and improves a formal calculation of Kac. Similar results are proved in higher dimensions. Up to the constant m(K), the quantity E
K
(t) can be interpreted as the expected value of the volume of the Wiener sausage associated with K and a d-dimensional Brownian motion. This point of view both plays a major role in the proofs and leads to a probabilistic interpretation of the different terms of the expansion. 相似文献