排序方式: 共有58条查询结果,搜索用时 484 毫秒
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Le Faou JH Suomijärvi T Blumenfeld Y Piattelli P Agodi C Alamanos N Alba R Auger F Bellia G Chomaz P Coniglione R Del Zoppo A Finocchiaro P Frascaria N Gaardhoje JJ Garron JP Gillibert A Lamehi-Rachti M Liguori-Neto R Maiolino C Migneco E Russo G Roynette JC Santonocito D Sapienza P Scarpaci JA Smerzi A 《Physical review letters》1994,72(21):3321-3324
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Akiba Y Beavis D Beery P Britt HC Budick B Chasman C Chen Z Chi CY Chu YY Cianciolo V Cole BA Costales JB Crawford HJ Cumming JB Debbe R Engelage J Fung SY Gonin M Gushue S Hamagaki H Hansen O Hayano RS Hayashi S Homma S Kaneko H Kang J Kaufman S Kehoe WL Kurita K Ledoux RJ Levine MJ Miake Y Morrison DP Morse RJ Moskowitz B Nagamiya S Namboodiri MN Nayak TK Olness J Parsons CG Remsberg LP Roehrich D Rothschild P Sakurai H Sangster TC Seto R Soltz R Stankus P Steadman SG Stephans GS Sung T 《Physical review letters》1996,76(12):2021-2024
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Lenhart JL van Zanten JH Dunkers JP Zimba CG James CA Pollack SK Parnas RS 《Journal of colloid and interface science》2000,221(1):75-86
Silane coupling agents are commonly applied to glass fibers to promote fiber/resin adhesion and enhance durability in composite parts. In this study, a coupling agent multilayer on glass was doped with trace levels of the dimethylaminonitrostilbene (DMANS) fluorophore. The fluorophore was immobilized on the glass surface by tethering the molecule to a triethoxy silane coupling agent, creating the DMANS/silane coupling agent molecule (DMSCA). DMSCA was then diluted with commonly used coupling agents and grafted to a glass microscope coverslip to create a model composite interface. A 53-nm blue shift in fluorescence from the immobilized DMSCA can be followed during cure of an epoxy resin overlayer, giving this technique potential to monitor the properties of the fiber/resin interface during composite processing. Contact angle measurements on these coupling agent layers were similar in the presence or absence of the DMSCA molecule, suggesting that trace levels of the fluorescent probe did not affect the structure of the layer. The immobilized DMSCA molecule behaved similarly to the DMANS precursor in solution. Both showed longer wavelength fluorescence in more polar environments. Copyright 2000 Academic Press. 相似文献
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Garcia Ruano JL Alemparte C Martin Castro AM Adams H Rodriguez Ramos JH 《The Journal of organic chemistry》2000,65(23):7938-7943
The behavior of (Z)-3-p-tolylsulfinylacrylonitrile (1) as a chiral dienophile has been evaluated from its reactions with furan and acyclic dienes. Electrostatic interactions of the cyano group with the sulfinyl one restrict the conformational mobility around the C-S bond, thus controlling the pi-facial selectivity, which is almost complete in all cases, the approach of the diene from the less-hindered face of the dienophile (that bearing the lone electron pair) in the predominant rotamer being the favored one. The regioselectivity is also completely controlled by the cyano group. Additionally, the reactivity of compound 1 as well as its endo-selectivity are both higher than those observed for the corresponding (Z)-3-sulfinylacrylates, thus proving the potential of sulfinylnitriles as chiral dienophiles. 相似文献
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Schmidt KS Filippov DV Meeuwenoord NJ van Der Marel GA van Boom JH Lippert B Reedijk J 《Angewandte Chemie (International ed. in English)》2000,39(2):375-377
Cross-linking ability is possible with the oligonucleotide-tethered, monofunctional trans-Pt(II) complex shown. It was synthesized by a novel solid-phase approach comprising conjugation of immobilized tetrathymidylic acid with a trans-a(2)Pt(II) building unit, ammonolysis, and transformation of the resulting complex (R=1-N-cyclohexylmethylthyminate) into the chloro derivative (R=Cl). a=NH(2)CH(3), T=thymine. 相似文献
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An experimental investigation of the gas-phase photooxidation of toluene–NOx–air mixtures at part-per-million concentrations has been carried out in a 65-m3, outdoor smog chamber to assess our understanding of the atmospheric chemistry of toluene. In addition, six CO? NOx–air irradiations were conducted to characterize the chamber with regard to any wall radical sources. Measured parameters in the toluene–NOx experiments included O3, NO, NO2, HNO3, peroxyacetyl nitrate (PAN), CO, toluene, benzaldehyde, o-cresol, m-nitrotoluene, peroxybenzoyl nitrate (PBZN), temperature, relative humidity, aerosol size distributions, and particulate organic carbon. Predictions of the reaction mechanism of Leone and Seinfeld [7] are found to be in good agreement with the data under a variety of initial conditions. Additional simulations are used to investigate various mechanistic pathways in areas where our understanding of toluene chemistry is still incomplete. 相似文献
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A scheme is proposed for the feedback control of distributed-parameter systems with unknown boundary and volume disturbances and observation errors. The scheme consists of employing a nonlinear filter in the control loop such that the controller uses the optimal estimates of the state of the system. A theoretical comparison of feedback proportional control of a styrene polymerization reactor with and without filtering is presented. It is indicated how an approximate filter can be constructed, greatly reducing the amount of computing required.Notation
a(t)
l-vector noisy dynamic input to system
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A(t, a)
l-vector function
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A
frequency factor for first-order rate law (5.68×106 sec–1)
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b
distance to the centerline between two coil banks in the reactor (4.7 cm)
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B
k-vector function defining the control action
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c(, )
concentration of styrene monomer, molel
–1
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C
p
heat capacity (0.43 cal · g–1 · K–1)
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C
ij
constants in approximate filter, Eqs. (49)–(52)
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E
activation energy (20330 cal · mole–1)
-
expectation operator
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f(t,...)
n-vector function
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g
0,g
1(t,...)
n-vector functions
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h(t, u)
m-vector function relating observations to states
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H(t)
function defined in Eq. (36)
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k
dimensionality of control vectorv(x, t)
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k
i
constants in approximate filter, Eqs. (49)–(52)
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K
dimensionless proportional gain
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l
dimensionality of dynamic inputa(t)
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m
dimensionality of observation vectory(t)
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n
dimensionality of state vectoru(x, t)
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P
(vv)(x, s, t)
n×n matrix governed by Eq. (9)
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P
(va)(x, t)
n×l matrix governed by Eq. (10)
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P
(aa)(t)
l×l matrix governed by Eq. (11)
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q
i
(t)
diagonal elements ofm×m matrixQ(x, s, t)
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Q(x, s, t)
m×m weighting matrix
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R
universal gas constant (1.987 cal · mole–1 · K–1)
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R(x, s, t)
n×n weighting matrix
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R
i
(t)
n×n weighting matrix
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s
dimensionless spatial variable
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S(x, s, t)
matrix defined in Eq. (11)
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t
dimensionless time variable
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T(, )
temperature, K
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u(x, t)
n-dimensional state vector
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u
c
(t)
wall temperature
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u
d
desired value ofu
1(1,t)
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u
c
*
reference control value ofu
c
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u
c
max
maximum value ofu
c
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u
c
min
minimum value of
c
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v(x, t)
k-dimensional control vector
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W(t)
l×l weighting matrix
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x
dimensionless spatial variable
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y(t)
m-dimensional observation vector
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i
constants in approximate filter, Eqs. (49)–(52)
-
dimensionless parameter defined in Eq. (29)
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H
heat of reaction (17500 cal · mole–1)
-
dimensionless activation energy, defined in Eq. (29)
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(x)
Dirac delta function
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(x, t)
m-dimensional observation noise
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thermal conductivity (0.43×10–3 cal · cm–1 · sec–1 · K–1)
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density (1 g · cm–3)
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time, sec
-
dimensionless parameter defined in Eq. (29)
-
spatial variable, cm
- *
reference value
- ^
estimated value 相似文献