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Many fruits are harvested at the early ripening stage and left to attain an edible stage during the post-ripening process or by ethylene treatment. However, the post-ripening quality of fruit is generally inferior to the quality of fruit that ripened naturally. Sugar metabolism plays critical roles in regulating fruit flavor and stress responses. Methyl Jasmonate (MeJA) treatment modulates sugar accumulations and postharvest fruit quality. However, the regulation mechanism of MeJA on sugar metabolism and its relationship with fruit post-ripening quality are unclear. The results indicated that MeJA-treated fruit possessed higher total antioxidant, lycopene and soluble solids content and lower electrical conductivity and malondialdehyde content. Besides, the post-ripening quality of fruit was strongly related to the starch and sucrose content. Compared to the control and ethephon treatments, MeJA treatment increased the activities and transcript levels of amylase, sucrose phosphate synthase (SPS) and sucrose synthase (SUS), but decreased the activities and transcript levels of acid invertase and neutral invertase. Further analysis suggested that the sucrose content had a strongly positive correlation with the activities and transcript levels of SUS and SPS, except SlSPS2. Thus, MeJA treatment improved fruit post-ripening quality by regulating sugar metabolism.

In temporal networks, PageRank-based methods are usually used to calculate the importance of nodes. However, almost all the methods focus on the first-order relationships between nodes while ignore higher-order interactions between nodes in the graph. Considering that temporal motifs are recurring, higher-order and significant network connectivity patterns, which can capture both temporal and higher-order structural features in dynamic networks, this paper proposes a novel Personalized Temporal Motif PageRank (PTMP) algorithm to measure the importance of nodes in temporal networks. Specifically, to capture temporal information and higher-order features, we develop a method extracting temporal motif instances from temporal networks, and design an algorithm to compute the weighted motif adjacency matrix and the diagonal motif out-degree matrix, then define a motif transition matrix, which contains the personalized feature and can be used to compute the importance score of nodes. Finally, we make the steady-state analysis for the PTMP algorithm and compare it with other state-of-the-art baselines on multiple real-world datasets. The experimental results demonstrate that the PTMP algorithm is capable of mining much richer important nodes information accurately and effectively.

The present research investigated the effect of annealing temperature on surface gradient fine microstructure and wear resistance of low-carbon steel. The results depicted that the optimized annealing temperature from 300 °C to 400 °C can facilitate the formation of a stable fine microstructure. The fine grain size is about 0.2 μm on the topmost surface layer, and the percentage of grain boundary with misorientation angle of 1.5° is 26 %. The full width at half maximum values gradually decreases with increasing temperature from room temperature to 600 °C. In addition, the abrasive wear dominates the entire process for samples annealed at 300-400 °C. The wear mechanism gradually switches to adhesive wear and even delamination wear when the annealing temperature is increased to 500-600 °C.

The phenol derivatives, as one kind of hormone, are analogous to endocrine disruptors with high carcinogenicity. The photocatalytic technology is an effective approach to mitigate environmental pollution by utilizing solar energy to degrade organic pollutants. In this work, CoPt hollow nanoparticles (NPs) attached to carbon nanotubes (CNTs) are employed to catalytically decompose the p-aminothiophenol (PATP) molecules under light irradiation, which is monitored by using surface-enhanced Raman scattering spectra. The effect of temperature on the catalytic efficacy of CoPt hollow NPs is investigated. Moreover, the use of CNTs coating on CoPt NPs is found to accelerate the photocatalytic degradation rate of PATP molecules, attributed to the enhanced plasmon-exciton coupling interaction of the CoPt/CNTs hybrid configuration.

The high-temperature wear properties of the gradient microstructure formed by ultrasonic impact treatment (UIT) on the surface of low-carbon steel are investigated. The dominant wear mechanism of the sample is oxidation wear and adhesive wear as the temperature increased from 300 °C to 500 °C. The wear mechanism of the sample changed from abrasive wear to fatigue wear as the applied load increased from 15 N to 95 N. The improvement in the high-temperature wear properties is due to the gradient nanocrystallization, which is helpful for forming an oxide film during wearing. As well as due to presence of the grain boundary wetting phase transitions of cementite, which can effectively delay the crack initiation.

Chilling acclimation and methyl jasmonate (MeJA) treatments are effective ways to alleviate chilling injury (CI) in postharvest fruit and vegetables. Soluble sugars can be used as an important energy substance, as well as an osmotic adjustment substance, participating in various stress responses in plants. However, the regulation mechanism of chilling acclimation and MeJA treatments on sugar metabolism remains unclear during the fruit response to chilling stress. In this study, tomato fruits were used to study the regulation of sugar metabolism during chilling resistance induced by 0.05 mM MeJA and 2 °C chilling acclimation treatments for 12 h and recovering at 25 °C for 6 h before being stored at 2 °C for up to 20 days. The results showed that both 2 °C and MeJA significantly induced chilling tolerance in tomato fruit, which was reflected by the decreased CI and malondialdehyde content, as well as the increased fruit color change and total antioxidant capacity. In addition, we found that 2 °C and MeJA promoted starch degradation and sucrose accumulation, but inhibited the increase of glucose and fructose contents. MeJA and 2 °C treatments enhanced the transcription levels of genes encoding amylase (AM), sucrose phosphate synthase (SPS), sucrose synthase (SuS) and neutral invertase (NI), while decreased the transcription level of gene encoding acid invertase (AI) during most of the storage periods. Further correlation analysis suggested that the chilling resistance of three groups of fruit was closely associated with sucrose content (r=−0.824 in control, r=−0.964 in 2 °C-treated fruit and r=−0.838 in MeJA-treated fruit); and the sucrose content of the fruit was positively correlated with SlSPS3 (r=0.681 in control, r=0.947 in 2 °C-treated fruit and r=0.889 in MeJA-treated fruit) and negatively correlated with SlAI (r=−0.954 in control, r=−0.921 in 2 °C-treated fruit and r=−0.637 in MeJA-treated fruit). In addition, in 2 °C-treated fruit, sucrose content was also correlated with the expression of a-AM (r=0.723), while in MeJA-treated fruit sucrose content was correlated with β-AM (r=0.694). These results suggested that 2 °C and MeJA treatments were both effective measures for enhancing the chilling resistance of tomato fruit by regulating sugar metabolism.

This study parsed the mechanism of SlMYC2 involving methyl jasmonate (MeJA)-mediated tomato fruit chilling tolerance. The data indicated that the application of MeJA significantly prevented chilling injury (CI) and inhibited the accumulation of hydrogen peroxide (H2O2) and superoxide anions (O2•−) in tomato fruit during cold storage. The accumulation of endogenous ascorbate (AsA) and glutathione (GSH) contents in fruit were enhanced by MeJA treatment resulting from increasing activities of enzymes related to AsA-GSH cycle. Meanwhile, the MeJA-treated fruit exhibited significantly higher expression levels of C-repeat-binding factor 1 (SlCBF1), cold regulated gene (SlCOR413) and inducer of SlCBF expression (SlICE1 and SlICEa), which belong to the SlICE-SlCBF-SlCOR (ICC) signaling pathway. However, the effects of MeJA were inhibited by the silence of SlMYC2. The expression levels of SlCBF1, SlCOR413, SlICE1 and SlICEa were reduced in SlMYC2-silenced fruits, and there was no significant difference in CI index and the indexes related to AsA-GSH cycle between (SlMYC2-silenced+MeJA)-treated fruit and control during most storage periods. In addition, correlation analysis indicated that the indexes involved in AsA-GSH cycle and ICC signaling pathway were closely related to the transcription of SlMYC2. Therefore, these results illustrated that SlMYC2 was involved in the regulation of ASA-GSH cycle and ICC signaling pathway mediated by MeJA during the cold tolerance of tomato fruit.

Chilling injury (CI) is a major limiting factor in the retention of the postharvest quality of chilling-sensitive vegetables and fruit stored at low temperatures. The enhanced chilling tolerance induced by methyl jasmonate (MeJA) treatment might be related to the polyamines biosynthesis. However, the molecular mechanism of polyamines biosynthesis induced by MeJA is far from clear. Here, we found that the application of 0.05 mmol L−1 MeJA enhanced the activities of arginase, arginine decarboxylase and ornithine decarboxylase, as well as the transcripts of SlARG1, SlARG2, SlADC and SlODC, promoted the accumulations of polyamines and further inhibited CI development. In addition, polyamines induced by MeJA were strongly positively correlated with the SlMYC2 expression level. Moreover, MeJA-induced polyamines biosynthesis was largely inhibited due to the silencing of SlMYC2. The (SlMYC2-silenced + MeJA)-treated fruit possessed higher incidence and index of CI than the MeJA-treated fruit. Combining these findings with results of the principal component analysis, we concluded that SlMYC2 is involved in MeJA-induced chilling tolerance in postharvest tomato fruit by regulating polyamines biosynthesis. Furthermore, the electrophoretic mobility shift and dual-luciferase reporter assays indicated that SlMYC2 could activate the transcription of SlARG1, SlARG2, SlADC and SlODC by binding directly to G/E-box elements in their promoters. From the findings, it was revealed that the targeted up-regulation of SlARG1, SlARG2, SlADC and SlODC by SlMYC2 is involved in MeJA-induced polyamines biosynthesis, which enhances chilling tolerance in tomato fruit.

The effect of stress and temperature coupling on gradient alloyed surfaces induced by punching severe deformation has been investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and microhardness tests. The stress field and temperature field were simulated using the Abaqus finite element method. The results show that surfaces experiencing the stress and temperature coupling effect have a greater depth of the alloying layer and a finer grain. In particular, the level of alloying, as determined by parameters such as the solid solubility of Cr atoms in a Fe crystal lattice and the quantity of the compound (Fe, Cr)7C3, is significantly increased. These differences are attributed to the coupling effect of stress and temperature, which can increase the number of crystal defects and the metallic Cr diffusion coefficient. Punching deformation without cooling treatment produces a higher hardness when compared to punching deformation with cooling treatment; without cooling treatment the hardness gradually decreases from 295 Hv at the top surface to 185 Hv in the matrix.

The present research investigated the effect of loads on high-temperature wear behavior of carbon steel with gradient microstructure. The results demonstrated that the gradient grain refinement was obtained, with grain size ranging from 0.1 to 3 μm. An increase in the coefficient of friction and wear volume was observed with the load increased. The wear mechanism of the sample changed from oxidation wear to delamination wear, with the load increased from 15 N to 75 N. Moreover, under low loads, it was found that a continuous oxide film was formed on the gradient surface, which retained the favorable high temperature wear properties. However, under high loads, the gradient layer was completely penetrated, and the low binding strength between the oxide film and the matrix resulted in the initiation and propagation of cracks, thereby exhibiting a poor wear performance of the sample.

The gradient alloying surface produced on a low-carbon steel material by a punching deformation and recovery process is investigated using scanning electron microscopy, energy disperse spectroscopy and X-ray diffraction. The mechanical properties of the gradient alloying surface are studied using nanoindentation and microhardness testers. The surface layer is observed to contain a (Fe,Cr) 7 C 3 phase. There is also a decrease in Cr content as grain size increases from the top surface to the matrix. These results can be attributed to defects in the microstructure induced by the punching deformation process, which promote diffusion of Cr in the matrix. The gradient alloying surface also exhibited increased hardness due to the grain refining process, the Cr solution used and the presence of the hard (Fe,Cr) 7 C 3 phase.

Para-aryl-dithiols (PADTs, HS-(C6H4)n-SH, n = 1, 2, and 3) have been used extensively in molecular electronics, surface-enhanced Raman spectroscopy (SERS), and quantum electron tunneling between two gold or silver nanoparticles (AuNPs and AgNPs). One popular belief is that these dithiols cross-link noble metal nanoparticles (NPs) as monolayer dithiolate spacers. Reported herein is our finding that PADTs predominantly exist as monothiolate forms on AuNPs or AgNPs. No PADT-induced NP cross-linking was observed regardless of the NP/PADT concentration ratios. Moreover, only one PADT thiol can be deprotonated even when PADTs are treated with concentrated NaOH or AgNO3 solutions. In contrast, 1,4-benzenedimethanethiol (HS-CH2-(C6H4)1-CH2-SH) and alkyl dithiol 1,2-ethanedithiol can be dithiolated on AuNPs and AgNPs, and in excess NaOH and AgNO3 solutions. This study should be of broad importance for plasmonic NP research given the popularity of PADTs in molecular electronics and SERS applications.

This paper concerns the global stabilization for a class of stochastic high-order nonlinear systems which admit more general system form than those in the existing works. For details, except for the serious system nonlinearities which show that the considered system is the general of the strict-feedback systems, the most distinct feature of the systems is exhibited by the unknown control directions, that is, all the control coefficients of the virtual and actual control have unknown signs. By skillfully employing the Nussbaum function, and applying the method of adding a power integrator, an effective regulation control scheme is successfully provided for the considered systems. In particular, the presented controller can guarantee that all the closed-loop system states are bounded, and especially the original system states converge to the origin, both in the sense of probability one.

The Raman and absorption spectra of a Ag2–PATP–Au2 junction adsorbed on graphene and boron-doped graphene were investigated by using density functional theory (DFT) and time-dependent DFT methods. The interactions between the graphene and junction result in charge transfer (CT) from the graphene to the junction due to their different work functions. This CT leads to charge redistribution on the junction, and then the changes of static polarizabilities, which directly influence the enhancement of normal Raman spectra. The absorption spectra show that the graphene and boron-doped graphene induce some CT excited states in the visible and infrared regions. When the energy of incident light is close to the energy of these CT excited states, these electronic transitions will be excited, which leads to the enhancement of pre-resonant Raman scattering (pre-RRS) spectra. In pre-RRS spectra, the B-doped model has stronger Raman intensities, since it produces more CT excited states with intense oscillator strength near the incident light than the graphene model. The non-totally symmetric modes (b2) are strongly enhanced as well as the totally symmetric modes (a1), indicating the contribution of Herzberg–Teller (HT) scattering. The charge difference densities (CDDs) method was employed to directly visualize the CT from the graphene sheet to the molecule.

We review our developed visualization method of charge transfer (CT) for chemical enhancement mechanism on surface-enhanced Raman scattering (SERS) and tip-enhanced Raman spectroscopy (TERS). Firstly, we describe our visualization method of charge difference density, which provides direct visual evidence for photoinduced CT. And then, using the visualization method of CT, we interpreted the mechanism of SERS and TERS. Photoinduced charge transfer in the processes of SERS and TERS can be clearly seen. Our visualization method provides a visual and easy understanding way for the mechanism of SERS and TERS. Copyright (C) 2014 John Wiley & Sons, Ltd.

The effect of ageing on the mechanical and impact properties of non-quenched and tempered steel wire strengthened by cold forming to an area reduction of 25.5% was investigated by tensile testing, charpy impact tests and scanning electronic microscopy. It was found that when the specimen was aged at 300 °C for 2 h, its tensile strength, yield strength, elongation and impact absorption energy increased by 10.8, 18.1, 44.8 and 19.6%, respectively. In addition the ductile-brittle transition temperature decreased by 5 °C. These improved properties are attributed to the decreasing dislocation density, the formation of sub-grains in a stable condition and the uniform dispersion of a fine precipitation phase during the ageing treatment.

Ultrasonic impact treatment (UIT) fabricated a gradient microstructure surface layer on carbon steel. The microstructural features were characterized by scanning electron microscopy, electron backscatter diffraction, and X-ray diffraction; the microhardness and wear behavior of the gradient microstructure surface were also studied. Results showed that an approximately 250 μm thick gradient microstructure was clearly observed, with low-angle grain boundaries and strong texture. The microhardness exhibited a gradient change of a depth of 269 HV in the top surface layer to 160 HV in the matrix. The wear mechanism changed from abrasive to fatigue wear when the sliding speed increased from 10 mm/s to 30 mm/s. Under sliding speeds of 10 mm/s and 20 mm/s, better wear resistance was attributable to the formation of oxides on the gradient microstructure surface. However, under the high speed of 30 mm/s, the gradient layer exhibited a high friction coefficient and wear rate.

When stacking with various underlying layers in the microelectronics devices, titanium nitride electrode films are not only desired to meet the critical requirements for high conductivity and low surface roughness, but also to be deposited over a wide processing window. In this work, a negative substrate bias was introduced as an additional power for the reactive sputtering of titanium nitride films. Upon systematically adjusting the substrate bias, working pressure and substrate temperature, the evolution of film properties was studied in detail in terms of resistivity, growth rate, crystal structure, surface morphology and composition. It was shown that an optimized substrate bias is beneficial for film densification and grain reorientation. As a result, titanium nitride films with superior-performance (resistivity ≤ 53.2 μΩ·cm and surface roughness ≤0.66 nm) can be grown over a wide working pressure range of 0.3–1.1 Pa and substrate temperature range from room temperature to 350 °C.

Ferroelectricity in calcium doped hafnium oxide (Ca:HfO2) thin films has been experimentally proved for the first time in this work. All films prepared by chemical solution deposition exhibited smooth and crack-free surfaces, which were observed using an atomic force microscope. After 104 field cycling, a maximum remanent polarization of 10.5 μC/cm2 was achieved in HfO2 films with 4.8 mol. % Ca content. Meanwhile, the breakdown of the film occurred after 7 × 106 electric cycles. A phase transition from the monoclinic phase to cubic/orthorhombic phases was observed with increasing Ca concentration. We suggest the change in oxygen vacancy concentration as the origin of phase evolution, which was confirmed by X-ray photoelectron spectroscopy analysis. These results open a new pathway for realizing ferroelectricity in HfO2-based films.

The punching severe deformation is a recently developed surface treatment that forms alloying by inducing a greater compressive equivalent stress field. Despite its proven utility, there has been little attention devoted to the accurate modeling of this process. In this work, a 3D-DEFORM finite element analysis was used to model the equivalent stress distribution induced by the punching process on a low-carbon steel surface. A majority of the controlling parameters of the process were taken into account. The effect of punching number, punching tip size, punching velocity and punching pressure on the equivalent stress distribution was evaluated. The results show that an equivalent stress distribution much higher than the conventional surface severe deformation can be obtained by optimizing the punching severe deformation process. The reported simulation results can successfully predict the punching severe deformation used to create an alloying layer on the surface of low-carbon steel.

Edible canna is a productive starch source in some tropical and semitropical regions. In these regions, water deficit stress is one of factors that limit the crop yield. In the present study, we investigated seven physiological indexes and photosynthetic responses of three edible canna (Canna edulis Ker.) cultivars (‘PLRF’, ‘Xingyu-1’, and ‘Xingyu-2’) under 35 days drought stress. Our results indicated that drought treatment caused visible wilting symptoms in all cultivars, especially in ‘Xingyu-1’. Coupled with the increase of wilting symptoms, relative water content (RWC) and chlorophyll content decreased progressively, malondialdehyde (MDA) content gradually increased, and key antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) activities increased first and then decreased in all three cultivars. The effect of water stress was more pronounced in ‘Xingyu-1’ than in ‘PLRF’ and ‘Xingyu-2’, and in lower leaves than in upper leaves. In addition, 35 days drought stress also significantly reduced the photosynthetic capacity. Consistent with antioxidant parameters, photosynthetic changes of ‘Xingyu-2’ were less than those of the other cultivars under water deficit stress. Drought stress caused a significant increase of water use efficiency (WUE) in ‘Xingyu-2’, but little in ‘PLRF’, and obvious decrease in ‘Xingyu-1’. These results indicated that ‘Xingyu-2’ was more tolerant to drought stress than ‘PLRF’ and ‘Xingyu-1’ by maintaining lower lipid peroxidation and higher antioxidant enzyme activities.

The influence of a static external electric field on surface-enhanced Raman scattering is investigated by calculating the Raman spectra and excited state properties of pyridine–Au20 complex with the density functional theory and time-dependent density functional theory method. The external electric field with orientation parallel (positive) or antiparallel (negative) to the permanent dipole moment is respectively applied on the complex. This field slightly changes the equilibrium geometry and polarizabilities, which results in shifted vibration frequencies and selectively enhanced Raman intensities. The changes of charge transfer (CT) excited states in response to the electric field are visualized by employing the charge difference densities. Further, the energy of charge transfer transition is tuned by electric field to be resonant or not with the incident light, leading to the Raman intensities are enhanced or not enhanced. At the same time, the intensities of vibration modes are sensitive to the orientation of the field. The positive electric field enhances the totally symmetric ring breathing mode (~1009 cm−1) but suppresses the trigonal ring breathing mode (~1051 cm−1). On the contrary, the mode at 1051 cm−1 is more enhanced than the mode at 1009 cm−1 when the negative electric field is applied on the complex. The Raman spectra could be modulated by tuning the strength and direction of the electric field. Copyright © 2013 John Wiley & Sons, Ltd.

The grain size variation in a gradient surface produced by a punching and recovery process on a Cu-30Ni alloy has been observed by atomic force microscopy. The friction characteristics of the gradient surface in a 3.5 wt% NaCl solution were investigated using a micro-indenter probe, a pin-on-disc type tribometer, a strain sensor and an optical microscope. The results showed that the hardness and grain size can be well represented by the Hall–Petch relationship when the gain size is more than 30 nm. The wear rate, friction coefficient and adhesive force all increase depth below the surface. These variations are attributed to a gradual increasing grain size with depth. The morphologies of the worn track were also studied to understand further the corrosive wear behaviour of gradient surfaces.

A punching process was employed to produce nanocrystalline on the surface of Cu-30Ni alloy. Compared with the original sample, corresponding changes of the grain size, mechanical properties and corrosion resistance of surface nanocrystalline induced by punching process were characterized by atomic force microscopy, nanoindentation, microhardness, electrochemical behavior and electron work function. It was observed that the grain size was about 40 nm in the topmost surface. The increasing mechanical properties were also demonstrated. Additionally, the dynamic polarization test showed that the surface nanocrystallization improved the resistance to electrochemical attacks. Such increasing corrosion resistance was identified with the higher EWF value. This study demonstrates that surface nanocrystallization can be generated by punching process, and thus mechanical properties and corrosion resistance of alloy can be improved.

The influence of annealing on the formation of nanocrystalline of CuNi alloy surface was investigated by evaluating the microstructure, mechanical properties, and corrosion behavior of as-processed condition (using severe plastic deformation by punching process) and its annealed condition. It was observed that the microstructure changed after annealing of punched sample using an atomic force microscope. Mechanical resistance and corrosion resistance were also characterized using nanoindentation test, electrochemical test, electron work function, and microtribometer test. It was found that the punched and subsequent annealed samples have increasing hardness, elastic behavior (η), and corrosion resistance. Therefore, annealing can lead to the final formation of nanocrystalline and corresponding stability of grain boundary, which are responsible for the increasing mechanical properties and corrosion resistance.

The physiological responses of three edible canna cultivars (Canna edulis ker. cv. ‘PLRF’, ‘Xingyu-1’, and ‘Xingyu-2’) to continuous drought stress for 35 days were investigated by characterizing the water saturation deficit (WSD), relative electrical conductivity (REC), superoxidative radical content (SRC), ascorbic acid (AsA) content, glutathione (GSH) content and protein content. It was observed that WSD, REC, SRC progressively increased in the upper leaves of three cultivars under both control and drought treatments. The content changes of AsA, GSH and water soluble protein were lower in ‘Xingyu-2’ than in ‘Xingyu-1’ and ‘PLRF’, in upper leaves than in lower leaves. Compared with control, drought stress aggravated these physiological changes in all three cultivars. The correlation analysis showed that there were significant correlations between indexes except for protein content, which significantly correlated only with SRC. These indicated that drought stress directly led to water loss, and then the REC increased, while the GSH and AsA played major roles in removing the SRC. These results revealed that ‘Xingyu-2’ was more tolerant to drought stress than ‘PLRF’ and ‘Xingyu-1’ and the lower leaves were more sensitive than the upper leaves. The present study not only provides new insights into mechanisms of acclimation and tolerance to drought stress in edible canna but also provides clues for improving drought tolerance of edible canna through breeding or genetic engineering.

In this study, malondialdehyde (MDA), relative conductivity (RC), superoxide anion (O2·−), hydrogen peroxide (H2O2), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) as well as ascorbic acid (AsA), glutation (GSH) and carotenoid (Car) were analyzed in plants under drought condition to investigate the enzymatic and non-enzymatic antioxidant defense mechanisms of leaves and petals, respectively. Two different drought resistance marigold cultivars (Tagetes erecta L. cv. Chokdee and Tagetes erecta L. cv. Discovery) treated with 6-day drought stress were used at early flowering stage. Results indicated that drought treatment increased MDA, RC, O2·− and H2O2 contents in the two cultivars, especially in drought-sensitive cultivar ‘Discovery’. In contrast, ‘Chokdee’ had higher level antioxidative enzyme activities and more non-enzymatic antioxidants than those in ‘Discovery’. SOD, POD, CAT, APX activities and non-enzymatic antioxidants (GSH and AsA) in the leaves and petals were increased at the beginning treatment, and decreased later. The activity of CAT in leaves and petals, APX in petals and AsA in petals on day 6 after treatment were lower than those in control, while Car in the two cultivars decreased consistently during drought stress treatment. In addition, all the antioxidant enzyme activities in the leaves were higher than those in petals, but AsA and GSH were accumulated at lower levels in leaves than those in petals of the both cultivars. Furthermore, significant linear relationships were found between antioxidative enzymes and reactive oxygen species (ROS), as well as in non-enzymatic antioxidants and ROS. In conclusion, drought tolerance of ‘Chokdee’ was correlated with eliminating the O2·− and H2O2 and maintaining lower lipid peroxidation as well as higher membrane stability by increasing activities of antioxidative enzymes and the amount of non-enzymatic antioxidants. Furthermore, different drought response mechanisms were involved in leaves and petals of marigold under drought stress.

Intermolecular charge transfer (ICT) enhanced resonance Raman scattering of charge transfer complex is investigated experimentally and theoretically. The evidence for intermolecular charge transfer on resonance electronic transition is visualized with charge difference density. The resonant Raman spectra reveal that the intensity of Raman peaks are strongly enhanced on the order of 104, by comparing with the normal Raman scattering spectrum. ICT complexes can be used in fluorescence-, photoluminescence-, and electrochemistry-based techniques for sensing target molecules. These strong charge-transfer Raman peaks would enable discrimination of important target molecules from interferants that is normal Raman scattering for the isolated target molecules.

Surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) spectra of the 1,4-benzenedithiol molecule in the junction of two Au3 clusters have been calculated using density functional theory (DFT) and time-dependent DFT method. In order to investigate the contribution of charge transfer (CT) enhancement, the wavelengths of incident light are chosen to be at resonance with four representative excited states, which correspond to CT in four different forms. Compared with SERS spectrum, SERRS spectra are enhanced enormously with distinct enhancement factors, which can be attributed to CT resonance in different forms.

The absorption spectra of dianionic tetrocyanoethylene and dicationic tetrathiafulvalene chillers have been studied theoretically with the time-dependent density functional theory and the recently proposed Coulomb-attenuated model. The nature of the excited states was further explored by means of the two-dimensional (2D) site (transition density matrix) and three-dimensional (3D) cube (transition density and charge difference density) representations. By use of the 3D transition density and charge difference density, we visualized the orientation of transition dipole moment and also explained charge-transfer characteristics occurring in the dianionic/dicationic pi-dimers system. It is found that for the dianionic/dicationic pi-dimers system there exist two kinds of charge-transfer patterns for the mainly excited states, the intermolecular charge transfer and the mixture of intramolecular charge transfer coupled with intermolecular charge transfer. Meanwhile, the coupling effect of excition and the oscillation of electron-hole pairs between the monomers have been revealed with 2-D site representation of transition density matrix, which also indicates the electron-hole coherence upon photon excitation.

We investigate surface-enhanced Raman scattering (SERS) spectra of pyridine-Ag(n) (n = 2-8) complexes by density functional theory (DFT) and time-dependent DFT (TDDFT) methods. In simulated normal Raman scattering (NRS) spectra, profiles of pyridine-Ag(n) (n = 2-8) complexes are analogical with that of isolated pyridine. Nevertheless, calculated pre-SERS spectra are strongly dependent on electronic transition states of new complexes. Wavelengths at 335 nm, 394.8 nm, 316.9 nm and 342.6 nm, which are nearly resonant with pure charge transfer excitation states, are adopted as incident light when simulating pre-SERS spectra for pyridine-Ag(n) (n = 2-8) complexes, respectively. We obtain enhancement factors from 10(3) to 10(5) in pre-SERS spectra compared with corresponding NRS spectra. The obvious increase in Raman intensities mainly result from charge transfer resonance Raman enhancement. A charge difference densities (CDDs) methodology is adopted in describing chemical enhancement mechanism. This methodology aims at visualizing charge transfer from Ag(n) (n = 2-8) clusters to pyridine on resonant electronic transition, which is one of the most direct evidences for chemical enhancement mechanism.

Based on the application of active networks in congestion control, this paper introduces the traditional congestion control policy and analyses their principles and feasibilities. Active networks congestion control policy introduces the active detection and the passive notification mechanism, the random early detect (RED) queue management and the load balance technology based on the traditional congestion control policy. It introduces active networks congestion control in the application of research and analysis the advantages and disadvantages of between the traditional congestion control policy and active networks congestion control policy.