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91.
In vivo noninvasive detection of chlorophyll distribution in cucumber (Cucumis sativus) leaves by indices based on hyperspectral imaging 总被引:2,自引:0,他引:2
The objective of this study was to investigate the spectral behavior of the relationship between reflectance and chlorophyll content and to develop a technique for non-destructive chlorophyll estimation and distribution in leaves using hyperspectral imaging. The hyperspectral imaging data cube of cucumber (Cucumis sativus) leaves in the range of 450-850 nm was investigated and preprocessed. Sixty optical signatures or indices as a function of the associated reflectance (R(λ)) at the special wavelength (λ) nm which proposed in the literatures were used to predict the total chlorophyll content in cucumber leaves. Finally, R(710)/R(760), (R(780)-R(710))/(R(780)-R(680)), (R(750)-R(705))/(R(750)+R(705)), (R(680)-R(430))/(R(680)+R(430)), R(860)/(R(550)×R(708)), (R(695-705))(-1)-(R(750-800))(-1), and REP-LEM (a index based on red edge position and estimated with a linear extrapolation method) were identified as optimum indices. Red-edge waveband (680-780 nm) appeared in all these optimum indices, indicating the importance of REP (red edge position) in chlorophyll estimation. When (R(695-705))(-1)-(R(750-800))(-1), the best index was applied to an independent validation set, chlorophyll content (r=0.8286) were reasonably well predicted, indicating model robustness. Depending on the sample, this technique enables to identify and characterize the relative content of various chlorophyll that distribution in the cucumber leaves. The map shows a relatively low level of chlorophyll at margins. Higher level can be noticed in the regions along the main veins and in some areas exhibiting dark green tissue. Our results indicate that hyperspectral imaging has considerable promise for predicting pigments in leaves and, the pigments can be detected in situ in living plant samples non-destructively. 相似文献
92.
Kwon TH Armel V Nattestad A Macfarlane DR Bach U Lind SJ Gordon KC Tang W Jones DJ Holmes AB 《The Journal of organic chemistry》2011,76(10):4088-4093
A one-pot synthesis of 2,6-dibromodithieno[3,2-b;2',3'-d]thiophene (dibromo-DTT, 4) was developed. A key step was bromodecarboxylation of DTT-2,6-dicarboxylic acid, obtained by saponification of the diester 1. The donor-acceptor dye DAHTDTT (13), based on a central 2,6-bis[2'-(3'-hexylthienyl)]dithieno[3,2-b;2',3'-d]thiophene core (9), was prepared and incorporated in a dye-sensitized solar cell (DSC), which exhibited an energy conversion efficiency of 7.3% with V(oc) of 697 mV, J(sc) of 14.4 mA/cm(2), and ff of 0.73 at 1 sun. 相似文献
93.
Summary We explore the relation between the classical continuum model of Euler buckling and an iterated mapping which is not only
a mathematical discretization of the former but also has an exact, discrete mechanical analogue. We show that the latter possesses
great numbers of “parasitic” solutions in addition to the natural discretizations of classical buckling modes. We investigate
this rich bifurcational structure using both mechanical analysis of the boundary value problem and dynamical studies of the
initial value problem, which is the familiar standard map. We use this example to explore the links between discrete initial
and boundary value problems and, more generally, to illustrate the complex relations among physical systems, continuum and
discrete models and the analytical and numerical methods for their study. 相似文献
94.
The spring-loaded inverted pendulum (SLIP) model describes well the steady-state center-of-mass motions of a diverse range
of walking and running animals and robots. Here we ask whether the SLIP model can also explain the dynamic stability of these
gaits, and we find that it cannot do so in many physically-relevant parameter ranges. We develop an actuated, lossy, clock-torqued
SLIP, or CT-SLIP, with more realistic hip-motor torque inputs, that can capture the robust stability properties observed in
most animals and some legged robots. Variations of CT-SLIP at a similar level of detail and complexity may also be appropriate
for capturing the whole-system center-of-mass dynamics of locomotion of legged animals and robots varying widely in size and
morphology. This paper contributes to a broader program to develop mathematical models, at varied levels of detail, that capture
the dynamics of integrated organismal systems exhibiting integrated whole-body motion.
相似文献
95.
J. W. Holmes 《Journal of fluorescence》1993,3(3):179-183
Aerodynamic tests are designed to give information about the performance of a model when subjected to an airflow. The introduction of pressure sensitive paint provides a new method for obtaining the pressure distribution on the surface of wind-tunnel models. A paint, the luminescence of which is dependent on air pressure, is applied to the surface of the model and the pressure distribution is obtained from the image produced. This paper gives an explanation of this technique, a résumé of possible applications and some results from research performed at DRA Bedford. 相似文献
96.
97.
This paper concerns Hamiltonian and non-Hamiltonian perturbations of integrable two degree of freedom Hamiltonian systems which contain homoclinic and periodic orbits. Our main example concerns perturbations of the uncoupled system consisting of the simple pendulum and the harmonic oscillator. We show that small coupling perturbations with, possibly, the addition of positive and negative damping breaks the integrability by introducing horseshoes into the dynamics.Research partially supported by ARO Contract DAAG-29-79-C-0086 and by NSF Grants ENG 78-02891 and MCS-78-06718 相似文献
98.
The mass spectra of maleic acid, maleic acid-2,3-d, fumaric acid and fumaric acid-2,3-d have been examined and fragmentation mechanisms are proposed for these compounds. The molecular ion of the cis-acid fragments via H atom transfer from one carboxyl group to the other followed by loss of CO2. The trans acid does not fragment significantly by this route and the former effect may be characteristic of molecules containing two carboxyl groups cis-oriented to each other. This hypothesis was successfully tested by examining the mass spectra of citraconic, itaconic and phthalic acids. Itaconic and mesaconic acids show some of the fragmentation characteristics of fumaric acid. 相似文献
99.
100.
Philip Holmes 《Applied Mathematical Modelling》1977,1(7):362-366
Some recent developments in dynamical systems theory are outlined and their physical implications are discussed. In particular we introduce the concept of ‘strange attractors’: motions which arise as solutions of deterministic dynamical systems but which have extremely complicated and apparently random structures. We suggest that the behaviour of such motions has serious consequences for dynamical modelling exercises. 相似文献