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Psoriasis is a common chronic inflammatory skin disease that is prone to recurrence, and the proinflammatory factor, cysteine-rich protein 61 (Cyr61), is important in its pathophysiology. Long-term clinical practice has shown that Sancao Formula (SC), a Chinese herbal compound, is effective in the treatment of psoriasis, but the precise mechanism remains unknown. In this study, we investigate the mechanism by which SC extract alleviates imiquimod (IMQ)-induced psoriasis.The expression of Cyr61 in psoriatic lesions and normal healthy skin was detected using immunohistochemical analysis to investigate the biological role of Cyr61 in models of psoriatic inflammation. A psoriatic mouse model was established by topical application of IMQ, and the effect of topical application of SC extract was evaluated using the psoriasis area and severity index (PASI) score, hematoxylin-eosin staining, and histopathological features of the skin. Next, a HaCaT cell inflammation model was established using interferon-γ (IFN-γ), and the effect of SC extract on the mRNA and protein levels of Cyr61 and intercellular cell adhesion molecule-1 (ICAM-1) was confirmed using Western blot and quantitative real-time polymerase chain reaction analyses.Immunohistochemical staining showed that the expression of Cyr61 in psoriatic lesions was higher than that in normal skin samples (78.26% vs 41.18%, P 0.05), and the number of Cyr61-positive cells in psoriatic lesions was also significantly higher than in normal skin (18.66 ± 2.51 vs 4.33 ± 1.52, P 0.05). Treatment in mice with IMQ-induced psoriasis showed that SC extract could significantly improve the inflammatory phenotype, PASI score (10.875 ± 0.744 vs 3.875 ± 0.582, P 0.05), and pathological features compared with those in IMQ model group; SC treatment was also associated with decreased levels of Cyr61 and ICAM-1. In the IFN-γ-induced inflammatory cell model, the mRNA and protein levels of Cyr61 and ICAM-1 were upregulated, while the SC extract downregulated the levels of Cyr61 and ICAM-1.The results provide a theoretical basis for the involvement of Cyr61 in the pathogenesis of psoriasis, and suggest that SC should be used to target Cyr61 for the prevention of psoriasis recurrence.

Disruption remains to be a serious threat to large tokamaks like ITER. The injection speed of disruption mitigation systems (DMS) driven by high pressure gas is limited by the sound speed of the propellent gas. When extrapolating to ITER-like tokamaks, long overall reaction duration and shallow penetration depth due to low injection speed make it stricter for Plasma Control System to predict the impending disruptions. Some disruptions with a short warning time may be unavoidable. Thus, a fast time response and high injection speed DMS is essential for large scale devices. Electromagnetic Pellet-Injection (EMPI) system is a novel massive material injection system aiming to provide rapid and effective disruption mitigation. Based on railgun concept, EMPI can accelerate the payload to over 1000 m/s and shorten the overall reaction time to a few milliseconds. To verify the injection ability and stability of the EMPI, the prototype injector EMPI-1 has been designed and assembled. The preliminary test has been carried out using a 5.9 g armature to propel a dummy pellet and the results suggest that the EMPI configuration has a great potential to be the DMS of the large scale fusion devices.

To obtain unconjugated hyperbranched polysiloxane (HBPSi), the triethoxyvinylsilane (A-151) and simple polyol compounds were used as raw materials, and two kinds of unconjugated HBPSi which the terminal group is -OH group and C=C bond were synthesized via a simply transesterification condensation, and the factors that affecting their luminescence are also further discussed. The results showed that, both of these two HBPSi exhibits excellent aggregate induced emission effect. The structure rich in π electrons or lone pair electrons in the raw materials basically maintains its original state in the polymer, and the spatial conjugation of the two leads to the luminescence of non-conjugated polymers. A large number of -OH groups in the polymer can form hydrogen bonds, and the promotion of hydrogen bonds makes the target products further gather spontaneously, which further enhances the spatial conjugation and improves the rigidity of the molecules. It can be concluded that under certain conditions, the larger steric hindrance of the molecule itself will affect the polymerization degree of the final product and the aggregation degree of the polymer molecule, while low polymerization and aggregation degree will result in higher energy required for the material to fluoresce. This study provides some reference significance for the preparation of non-conjugated luminescent materials with higher fluorescence intensity.

BackgroundAt present, the conclusions about the impact of hypertensive disorders of pregnancy (HDP) on the clinical outcomes of preterm infants are inconsistent. This study used the propensity score matching (PSM) analysis to evaluate the effect of HDP on clinical outcomes of extremely preterm or extremely low birth weight (EP/ELBW) infants.MethodsRetrospective analysis was performed on the EP/ELBW infants discharged from 26 tertiary neonatal intensive care units or died during hospitalization from 2008 to 2017, who were divided into HDP group and non-HDP group. The six covariates including sex, gestational age, birth weight, twin or multiple pregnancy, antenatal steroids administration, and conception method were matched through the PSM method at a ratio of 1:1. The survival rate at discharge and the major clinical complications were compared between the two groups.ResultsAfter matching the six covariates, compared with the non-HDP group, there was no significant difference in the survival rate at discharge (64 vs. 63.2%, p > 0.05), the incidence of bronchopulmonary dysplasia (BPD) or moderate to severe BPD in the HDP group (58.3 vs. 54.9%, p > 0.05; 5.2 vs. 6.2%, p > 0.05). The incidence of periventricular leukomalacia (PVL) in the HDP group was significantly increased (5.7 vs. 1.9%, p < 0.05).ConclusionsHDP increased the risk of PVL in EP/ELBW infants, but had no significant effect on the survival rate at discharge, or the occurrence of other complications.

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Approximately 40% of mammalian genome is made of transposable elements (TEs), and during specific biological processes, such as gametogenesis, they may be activated by global demethylation, so strict silencing mechanism is indispensable for genomic stability. Here, we performed small RNA-seq on Dicer1 knockdown (KD) oocytes in pig, and observed short interspersed nuclear elements 1B (SINE1B) derived endogenous small interfering RNAs (endo-siRNAs), termed SINE1B-siRNAs, were significantly decreased and their biogenesis was dependent on Dicer1 and transcript of SINE1B. Furthermore, by injection of mimics and inhibitors of the SINE1B-siRNAs into germinal vesicle-stage (GV-stage) oocytes, we found the maturation rate was significantly decreased by SINE1B-siRNAs, indicating the SINE1B-siRNAs are indispensible for in vitro maturation (IVM) of porcine oocyte. To figure out the mechanism, we checked the expression pattern and DNA methylation status of SINE1B during IVM of porcine oocytes, and demonstrated the SINE1B-siRNAs could repress SINE1B expression induced by hypomethylation at a post-transcriptional level. Our results suggest that during gametogenesis when the erasure of DNA methylation occurs, endo-siRNAs act as a chronic response to limit retrotransposon activation.

Recent works have generally indicated that insects exhibit two immune response strategies: external and internal immune defense. However, the immune-related trade-offs and physiological regulatory mechanisms in red palm weevil, a major invasive pest, remain unclear. Based on postinfection survivorship experiments, we initially measured baseline constitutive external immunity (antibacterial activity of external secretions) and internal immunity (phenoloxidase and antibacterial activity of hemolymph) in uninfected individuals. Then, we challenged the individual immune system and examined subsequent investment in immune function. Our data showed that multiple factors (instar, age, sex, mating status, immune treatment) interacted to affect immune components and infection outcomes, but the magnitude and nature of the impact varied in each case. Although immune senescence is a common phenomenon in which immune function decreases with age, different components of the immune system changed differentially. Notably, mating activity may impose an immunity-related cost, with some evidence of sexual dimorphism and age-associated differences. Finally, parameters related to life-history traits usually decreased temporarily because of increased immunity, suggesting that the ultimate consequences of immune function fitness may be physiologically traded off with other fitness aspects, including growth, development, mating, reproduction, and longevity. These results reveal the complex factors that impact immunity as well as the physiological regulation of individual immunity, which may determine the evolution and outcome of immune senescence and trade-offs.

AU-GSB e-Journal, 14, 2, 118-129

In this study, we propose a simple and effective approach to enhance (110) orientation in diamond films grown on (100) Si substrates by microwave plasma chemical vapor deposition. It is found that the crystalline structure of diamond films strongly rely on the CH4 concentration in the nucleation stage. Under the same growth condition, when the CH4 concentration is less than 7% (7%) in the nucleation stage, the diamond films exhibit randomly oriented structure; once the value exceeds 7%, the deposited films are strongly (110) oriented. It could be verified by experiments that the formation of (110) orientation in diamond films are related to the high nucleation density and high fraction of diamond-like carbon existing in nucleation samples.

Cracks in concrete structures can indicate major structural problems and can harm the appearance of monolithic construction. This article presents a new approach in image processing for detecting cracks in images of concrete structures. This method involves three steps: First; change the image to a gray and using edge of the image and use Sobel's method and development of an image filter using Sobel's filter for detecting cracks. Second; using a suitable threshold in a binary image and classifies all pixels two categorizations background and foreground, and gets the region area after that use filter area and changes the area if less than the specific number to back. Third; after using Sobel's filtering to elimination of residual noise, and detecting major cracks using Otsu method. This paper describes a method for detection crack patterns in cement use image processing techniques. The advantage of this method is clearly and accurate detection of cracks in images. Experimental work shows that our method is improved relatively to the other widely used techniques.

In this paper, high-order moment, even exponential moment, estimates are established for the H\"older norm of solutions to stochastic differential equations driven by fractional Brownian motion whose drifts are measurable and have linear growth. As applications, we first study the weak uniqueness of solutions to fractional stochastic differential equations. Moreover, combining our estimates and the Fourier transform, we establish the existence of density of solutions to equations with irregular drifts., Comment: 25 pages

Engineering layer-layer interactions provides a powerful way to realize novel and designable quantum phenomena in van der Waals heterostructures. Interlayer electron-electron interactions, for example, have enabled fascinating physics that is difficult to achieve in a single material, such as the Hofstadter's butterfly in graphene/boron nitride (hBN) heterostructures. In addition to electron-electron interactions, interlayer electron-phonon interactions allow for further control of the physical properties of van der Waals heterostructures. Here we report an interlayer electron-phonon interaction in WSe 2 /hBN heterostructures, where optically silent hBN phonons emerge in Raman spectra with strong intensities through resonant coupling to WSe 2 electronic transitions. Excitation spectroscopy reveals the double-resonance nature of such enhancement, and identifies the two resonant states to be the A exciton transition of monolayer WSe 2 and a new hybrid state present only in WSe 2 /hBN heterostructures. The observation of an interlayer electron-phonon interaction could open up new ways to engineer electrons and phonons for device applications.

From the previous researches, the author of this paper finds that the steel tube with the hexagonal section under the lateral compression has a good energy absorption property. In order to further enhance the energy absorption of the steel tube with the hexagonal section, this paper develops the polyurethane foam filled hexagonal steel tube, and through experiment, studies its characteristics of lateral compression energy absorption, and makes the comparative analysis against the hollow hexagonal steel tube. The results show that the hexagonal section steel tube filled with polyurethane foam has substantially growth in both the loads of the yield platform and the energy absorption capability.

Using the numerical solution of the full Maxwell-Bloch equations without the slowly varying envelope approximation and the rotating-wave approximation, propagation behavior of few-cycle laser pulse in a dense ladder-type three-level atomic medium is investigated and it is compared with the case in the corresponding dilute medium. It is found that, in the propagation process, time evolution of the pulse in the dense medium is obviously different from that in the dilute medium, and the difference will become more evident with increasing of the initial pulse area. When the initial pulse area is smaller, in the propagating process, the pulse shape in the dilute medium just have a small change; the pulse shape in the dense medium has considerable variation but the pulse splitting doesn't occur. When the initial pulse area is larger enough, for the dense medium case, the pulse splits into sub-pulses with different numbers and shapes at different propagation distances; while for the dilute medium case, variation of the pulse shape is still smaller in propagation process. The cause producing above difference is from two effects in the dense medium: the effect of the local-field correction (LFC) from the near dipole-dipole interaction and effect of stronger polarization field than that in the dilute medium. In which the effect of stronger polarization field plays a main role, but the role of LFC also cannot be neglected,and the stronger polarization field is due to the atomic density increasing .

A study is made of the effects of Doppler broadening on pure gain without inversion, which means that neither one-photon nor two-photon inversions are allowed, and non-pure gain without inversion, which means that one-photon inversion does not occur but two-photon inversion is present, in a closed Λ-type three-level system with incoherent pumping. It is shown that when the driving field is resonant but the probe field is not, in a certain range of Doppler width, for the case of the lower degree of frequency up-conversion, generally, pure gain without inversion increases monotonically and non-pure gain without inversion does not monotonically increase or decrease with increasing Doppler width; for the case of the higher degree of frequency up-conversion, pure gain without inversion decreases monotonically but non-pure gain without inversion cannot be produced. In the case of two-photon resonance, in some range of Doppler width, pure gain without inversion does not monotonically increase or decrease while non-pure gain without inversion decreases monotonically with Doppler width increasing. Finally, an experimental scheme for examining our theoretical result is given.

Activation tagging plays an important role in plant genomics studies. In this paper, an activation tagging library containing 50 000 Basta-resistant lines was constructed by mediated transformation of the mutantbzr1-DofAribidopsis thaliana. Among these transformants, 47 lines showed obvious phenotypes, including late flowering time, dwarf growth habit, changed leaf shape, longer leaf petiole, leaves lacking trichomes, sterility and no kink between stem/leaf. Some T-DNA flanking sequences were obtained by TAIL (thermal asymmetric interlaced) and nested PCR. Results showed that the mutants contained one to three T-DNA insertions. The insertions were distributed in the first, fourth and fifth chromosomes of the genome.

This paper studies the propagation effect in a closed lambda-type three-level atomic system with Doppler broadening. It is shown that, Doppler broadening due to atomic motion and propagation effect associated with driving field depletion along the active medium decreases obviously the gain and output of the lasing without inversion (LWI); the relative phase between the probe and driving fields has a remarkable modulation role to the propagation effect on LWI when Doppler broadening presents; by choosing suitable value of the relative phase, we can get the largest gain and output of LWI.

The effects of annealing on the chemical states of N dopant, electrical, and optical properties of N-doped ZnO film grown by molecular beam epitaxy (MBE) are investigated. Both the as-grown ZnO:N film and the film annealed in N2 are of n-type conductivity, whereas the conductivity converts into p-type conductivity for the film annealed in O2. We suggest that the transformation of conductivity is ascribed to the change in ratio of the N molecular number on O site (N2)O to the N atom number on O site (NO) in ZnO:N films under the various annealed atmosphere. For the ZnO:N film annealed in N2, the percentage content of (N2)O is larger than that of NO, i.e. the ratio > 1, resulting in the n-type conductivity. However, in the case of the ZnO:N film annealed in O2, the percentage content of (N2)O is fewer than that of NO, i.e., the ratio < 1, giving rise to the p-type conductivity. There is an obvious difference between low-temperature (80 K) PL spectra of ZnO:N film annealed in N2 and that of ZnO:N film annealed in O2. An emission band located at 3.358 eV is observed in the spectra of the ZnO:N film after annealed in N2, this emission band is due to donor-bound exciton (D0X). After annealed in O2, the PL of the donor-bound exciton disappeared, an emission band located at 3.348 eV is observed, this emission band is assigned to acceptor-bound exciton (A0X).

The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schrodinger equation without including the rotating wave approximation (RWA). It is shown that population transfer is mainly determined by the Rabi frequency (strength) of the driving laser field and the chirp rate, and that the ratio of the dipole moments and the pulse width also have a prominent effect on the population transfer. By choosing appropriate values of the above parameters, complete population transfer can be realized.

An analysis is made of the effect of Doppler broadening on gain without inversion (GWI) from different aspects in a closed lambda-type three-level system with an incoherent pump. It is shown that, regardless of the driving field being on resonance or not, for the counter- or co-propagating of the probe and driving fields (PDF), GWI does not monotonically decrease or increase with increasing Doppler width. Except for the case of counter-propagating PDF with off-resonance driving field, at a suitable Doppler width one can obtain a gain maximum value much larger than that without Doppler broadening; especially in the situation of the resonant driving field, the co-propagating geometry leads to a larger GWI. In addition, for the counter-propagating geometry, when Doppler width is larger enough, GWI oscillation occurs, and the oscillation amplitude and region increase with increasing Doppler width. These conclusions are very different from that obtained in previous investigation (Lukin et al, Laser Phys. 6 436 (1996)).

The phenomena of electron, neutron, atomic and molecular diffraction have been studied by many experiments, and these experiments are explained by some theoretical works. In this paper, we study electronic double-slit diffraction with quantum mechanical approach. We can obtain the results: (1) When the slit width $a$ is in the range of $3\lambda\sim 50\lambda$ we can obtain the obvious diffraction patterns. (2) when the ratio of $\frac{d+a}{a}=n (n=1, 2, 3,\cdot\cdot\cdot)$, order $2n, 3n, 4n,\cdot\cdot\cdot$ are missing in diffraction pattern. (3)When the ratio of $\frac{d+a}{a}\neq n (n=1, 2, 3,\cdot\cdot\cdot)$, there isn't missing order in diffraction pattern. (4) We also find a new quantum mechanics effect that the slit thickness $c$ has a large affect to the electronic diffraction patterns. We think all the predictions in our work can be tested by the electronic double-slit diffraction experiment., Comment: 9pages, 14figures

Phenomena of electron, neutron, atomic and molecular diffraction have been studied in many experiments, and these experiments are explained by many theoretical works. We study neutron single-slit diffraction with a quantum mechanical approach. It is found that the obvious diffraction patterns can be obtained when the single-slit width a is in the range of 3λ~60λ. We also find a new quantum effect of the thickness of single-slit which can make a large impact on the diffraction pattern. The new quantum effect predicted in our work can be tested by the neutron single-slit diffraction experiment.

This paper investigates the control role of the relative phase between the probe and driving fields on the gain, dispersion and populations in an open Λ system with spontaneously generated coherence (SGC). It shows that by adjusting the value of the relative phase, a change from lasing with inversion to lasing without inversion can be realized; the values and frequency spectrum regions of the inversionless gain and dispersion can be obviously varied; high refractive index with zero absorption and electromagnetically induced transparency can be achieved. It is also found that when the driving field is resonant, the shapes of the dispersion and the gain curves versus the probe detuning are very similar if the relative phase of the dispersion lags π/2 than that of the gain, however for the off-resonant driving field the similarity will disappear; the gain, dispersion and populations are periodical functions of the relative phase, the modulation period is always 2π; the contribution of SGC to the inversionless gain and dispersion is much larger than that of the dynamically induced coherence.

To recognize the type of welding joint is an essential precondition for extracting features of weld seam and guiding robot tracking seam automatically. A method based on a line laser structured-light vision for recognizing the type of welding joint is studied in this paper. Images of welding joint captured by camera are preprocessed firstly for noise reduction and enhancement with wavelet transform, and the reconstructed images are converted to binary ones using appropriate thresholds. Then some features of binary images are further extracted and formed feature vectors which are input into a PNN classifier for classification. Combined with the position relationship of laser and camera, four types of welding joint are eventually recognized. Experimental results show that, this method has a high recognition rate.

The military communication system is the key element to make a victory in the battle. In general, the combat collaborative communication network is a multi-hop and autonomous system, which is composed by a group of mobile nodes with wireless communication ability. The network has some features such as no center, self-organizing, multi-hop routing and dynamic topology. Because of the bandwidth limitation and host energy restriction, this kind of network has some weaknesses during the operation, such as long time to establish routing, overmuch maintenance information, weak anti-damage ability and low transfer efficiency. The new dynamic routing algorithm in this paper, which combines the location information with intelligent ant colony algorithm, can quickly update the dynamic routing table and improve the linkage robustness. This paper also verifies the algorithm by the OPNet and compares the algorithm with the traditional routing protocols. The results demonstrate that the new algorithm can effectively reduce routing maintenance information, shorten the route setting-up time, and improve the routing forwarding and anti-jamming ability during information transmission.

TiO2−xNx thin films are deposited onto Si(100) and quartz substrates by a rf magnetron sputtering method using a titanium metal disc as a target in Ar, N2, and O2 atmospheres. The substrate temperature is kept at 300°C. The O2 and Ar gas flow rates are kept to be constants and the N gas flow rate is varied. TiO2−xNx films with different N contents are characterized by x-ray diffraction and x-ray photoelectron spectroscopy. The results indicate that the TiO2−xNx thin films can be obtained at 13% N and 15% N contents in the film, and the films with mixed TiO2 and TiN crystal can be obtained at 13% N and 15% N contents in the film. In terms of the results of x-ray photoelectron spectroscopy, N 1s of β-N (396 eV) is the main component in the TiO2−xNx thin films. Because the energy level of β-N is positioned above the valence-band maximum of TiO2, an effective optical-energy gap decreases from 2.8 eV (for pure TiO2 film deposited by the same rf sputtering system) to 2.3 eV, which is verified by the optical-absorption spectra.

We investigate the origin of ultraviolet (UV) emission from Mg0.12Zn0.88O alloy thin films with a wurtzite structure fabricated on c-plane Al2O3 substrates by plasma assisted molecular beam epitaxy. At room temperature, the absorption edge and UV emission band of the Mg0.12Zn0.88O film shift to high-energy side compared with ZnO films. Temperature dependence of the photoluminescence spectra shows that the UV emission is composed of free exciton and neutral donor bound exciton emissions. Two-step dissociation processes of the UV emission are observed with the increasing temperature. The thermal quenching mechanism is attributed to the dissociation of the free exciton from the neutral donor bound exciton in the low temperature region and the dissociation of free electron and hole from the free exciton in the high temperature region.

ZnO nanotubes were epitaxially grown on a Si(I 1 1) substrate by plasma-assisted molecular beam epitaxy using a two-step process. First, a low-temperature ZnO layer was deposited on the Si substrate at a temperature of 300 degrees C, which was treated by an O-2(+) -plasma for 30 min. Second, a ZnO layer that showed tubular-like nanostructure was grown on this treated layer at 550 degrees C using the same flow rate of the 02 and zinc. No catalyst or templates were required for the formation of the ZnO nanotubes. Field-emission scanning electron microscopy (SEM) and X-ray power diffraction (XRD) experiments showed that the ZnO nanotubes were single crystals of pure hexagonal wurtzite structure growing along the [0 0 0 2] direction. The diameters of the nanotubes were in a range of 10-90 nm, and the average size of the nanotubes was 50 nm. Room-temperature photoluminescence (PL) measurements of the ZnO nanotubes showed ultraviolet peaks at 3.290 eV with a full-width at half-maximum (FWHM) of 104 meV, which was comparable to those found in high-quality ZnO films. The PL spectrum at 81 K showed a sharp free-exciton emission with an FWHM of 22.1 meV. The SEM, XRD and PL results indicated that the prepared ZnO nanotubes have potential applications in optoelectronic devices. Possible reasons for the growth of ZnO nanotubes were discussed. (c) 2005 Elsevier B.V. All rights reserved.

A coupling structure of CdSe quantum dots (QDs) and a ZnCdSe quantum well (QW) is fabricated by using the molecular-beam epitaxy technique. The effect of temperature on the photoluminescence (PL) of the structure is studied. The results reveal that the activation energy of exciton dissociation in the coupling QDs/QW structure is much higher than that of simple CdSe QDs, which is attributed to the exciton tunnelling from the QW to QDs through a thin ZnSe barrier layer. The results also reveal that the position and width of the emission band of the QDs vary discontinuously at certain temperatures. This phenomenon is explained by the QD ionization and exciton tunnelling from the QW to the QDs. It is demonstrated that the coupling structure significantly improves the PL intensity of CdSe QDs.

Room-temperature P-band emission induced by an exciton–exciton collision process was observed in ZnO micro-rods. Both temperature- and excitation-intensity-dependent photoluminescence (PL) measurements were conducted. The excitation-intensity-dependent measurement illustrated that the P-band emission could occur at far lower excitation intensity than that reported in the literature. Higher-order transitions were also observed at the excitation intensity of 7.1 kW/cm2 or above. The temperature-dependent PL showed that the P-band emission process was thermally activated. It is suggested that both the density and activity of free excitons played important roles in the exciton–exciton collision process.

ZnTe films have been prepared on Si substrates by metal-organic chemical vapour deposition (MOCVD), and the temperature-dependent photoluminescence (PL) properties were investigated. The near-band-edge (NBE) emission of the ZnTe sample at 83 K shows an asymmetry line shape, which can be decomposed into two Gaussian lines labelled by FE and BE. Temperature-dependent PL intensity of the NBE peak shows two variation regions, and an expression with two dissociation channels fits well to the experimental data. The results of the temperature-dependent full width at half maximum (FWHM) and peak energy were well understood under the framework of the two-dissociation-channel model. That is, at low temperature, the emission from bound excitons governs the NBE peak, while above 157 K, the free exciton emission becomes dominant gradually. A simple model with three energy levels was employed to describe the variation in emission intensity of BE and FE with temperature.

We present a simple and useful method for preparing high-quality nanocrystalline ZnO thin films, i.e. the thermal oxidation of high-quality ZnS films prepared by the low-pressure metal-organic chemical vapour deposition technique. The x-ray diffraction measurements reveal that the nanocrystalline ZnO has a hexagonal wurtzite structure. Raman spectra show that the longitudinal optical phonon with the E1-mode appears at 578 cm-1. The multiple phonon scattering process is also observed, indicating the formation of a high-quality nanocrystalline ZnO thin film. The photoluminescence spectrum has a single emission peak at 3.264 eV from the free-exciton mission, under the condition of low excitation power at room temperature. However, when excitation intensities exceed the threshold of 150 kW/cm2, a new and narrow peak emerges at lower energies, which are attributed to exciton-exciton collisions, and is called the P line. The intensity of this peak increases superlinearly with the pumping power over a threshold value. This supplies strong evidence of stimulated emission. The multiple longitudinal cavity modes observed in the stimulated emission spectrum indicate the successful realization of optically pumped lasing from nanocrystalline ZnO films at room temperature.

An exact nonlinear analytical solution of an open V-type inversionless lasing system with two incoherent pump fields, off-resonant driving and probe fields is given. Through qualitative and quantitative comparison of the gain, dispersion and population differences of the linear and nonlinear cases, some conclusions concerning the Rabi frequencies of the driving and the probe fields are drawn and discussed in detail.

By using the combination of the first-nearest neighbor tight-binding model sp3s* and Green function method in the frame of the scattering theory, we studied the electronic structure of ZnTe/CdSe(100) heterojunction with cation layers interchange across ZnSe-like or CdTe-like interface, and presented the interface band structures and wavevector-resolved interface layer densities of states. By comparing with the electronic states of ideal interfaces, we analyzed the nature and origins of all interface states, and discussed the influence of atom layers interchange on interface electronic structure.

A series of Cd0.44Zn0.56Se/ZnSe sandwich structures with different Cd0.44Zn0.56Se embedded layer thicknesses were fabricated by metal organic chemical vapor deposition. When the embedded layer thickness exceeded 3.0 nm, the photoluminescence spectra of the sample changed into the two-band structure from the one-band structure, and atomic force microscopy images indicate that Cd0.44Zn0.56Se quantum dots were formed. In the two-band photoluminescence spectrum, the band at the low energy side was attributed to be from quantum dots, and the high-energy one arose from the wetting layer. Thinning of the wetting layer with quantum dots forming was confirmed indirectly by the significant blue shift of the wetting-layer photoluminescence band compared to the photoluminescence band of the samples for which the Cd0.44Zn0.56Se layer thickness was less than 3.0 nm. This thinning arose from mass migration during the Stranski–Krastanow growth of Cd0.44Zn0.56Se quantum dots.

The comprehensive electronic information systems architecture is an important part of arming information-based construction, so the architecture description approach is needed to be studied with the system optimization simultaneously. In order to support system optimization, an architecture description approach of information systems is studied with the multi-perspective point’s method. Based on the data of the architecture description models, this article will analysis the data form of the description model and the logic relation of the data therefore the architecture description models can be used to optimize information systems architecture . DOI: http://dx.doi.org/10.11591/telkomnika.v11i3.2210

The room-temperature blue cathodoluminescence (CL) from highly Er-doped ZnO thin films has been studied by using different electron beam currents (EBCs). The ZnO:Er thin films used in our experiment were prepared by simultaneous evaporation from two sources. The x-ray diffraction spectra show that the thin films have a strong preferential c-axis (0002) orientation with a hexagonal crystalline structure. The blue emission at 455 nm originating from the intra-4f shell transition (4F5/24I15/2) in Er3+ ions was observed at room temperature. The nonlinear dependence of the CL intensity on the EBC shows a more intense blue emission above the threshold EBC of 0.6 µA, which is attributed to the phonon bottleneck effect.

In the paper, Harnack inequalities are established for stochastic differential equations driven by fractional Brownian motion with Hurst parameter $H

In this paper, we give the spinor wave equations of free and unfree photon, which are the differential equation of space-time one order. For the free photon, the spinor wave equations are covariant, and the spinors $\psi$ are corresponding to the the reducibility representations $D^{10}+D^{01}$ and $D^{10}+D^{01}+D^{1/2 1/2}$ of the proper Lorentz group.

We study the optical properties of ZnCdSe/ZnMgSe multiple quantum wells using photoluminescence (PL) and Raman scattering spectra. In the PL spectra, an intense emission band coming from the free exciton luminescence of the quantum wells can be observed from 80 K to 300 K. The exciton binding energy is evaluated by the dependence of PL intensity on the temperature, showing the behaviour of the better two-dimensional excitons. The result indicates that the enhancement of the confinement effect is due to containing Mg in the barrier layers. At room temperature, Raman scattering spectra are classified into confined optical modes and folded optical modes. This confirms the formation of a multilayer system with a higher crystalline quality.

A temperature-dependent photoluminescence measurement is performed in CdSe/ZnSe quantum dots with a ZnCdSe quantum well. We deduce the temperature dependence of the exciton linewidth and peak energy of the zero-dimensional exciton in the quantum dots and two-dimensional exciton in the CdSe wetting layer. The experimental data reveal a reduction of homogeneous broadening of the exciton line in the quantum dots in comparison with that in the two-dimensional wetting layer, which indicates the decrease of exciton and optical phonon coupling in the CdSe quantum dots.

We study the photoluminescence (PL) of ultra thin layer ZnSe quantum wells in ZnS barriers. Samples with different well widths are grown by vapour phase epitaxy and the PL spectra of these samples are measured by the excitation of a 500 W Hg lamp. The peak positions of the bands coming from the excitonic luminescence show a larger blueshift with respect to the energy of free excitons in the ZnSe bulk material. The observed variation of the full width at half maximum and peak position of the bands in the spectra with the well width are interpreted to the formation of the ZnSxSe1-x alloy layer due to the interdiffusion in the interfaces between ZnSe and ZnS. According to the behaviour of the excitons in the smaller conduction band offset, the exciton binding energy is estimated from the dependence of the PL intensity on the temperature. From this result, excitons seem to show nearly three-dimensional characteristics.

The effects of thermal annealing on photoluminescence (PL) and structural properties of a-Si1-xCx:H films deposited by plasma enhanced chemical vapour deposition from CH4+SiH4 mixtures are studied by using infrared, PL and transmittance-reflectance spectra. In a-SiC:H network, high-temperature annealing gives rise to the effusion of hydrogen from strongly bonded hydrogen in SiH, SiH2, (SiH2)n, SiCHn and CHn configurations and the break of weak C-C, Si-Si and C-Si bonds. A structural rearrangement will occur, which causes a significant correlation of the position and intensity of the PL signal with the annealing temperature. The redshift of the PL peak is related to the destruction of the confining power of barriers. However, the PL intensity does not have a significant correlation with the annealing temperature for a C-rich a-SiC:H network, which refers to the formation of π-bond cluster as increasing carbon content. It is indicated that the thermal stability of C-rich a-Si1-xCx:H films is better than that of Si-like a-Si1-xCx:H films. PACS: 78. 55. Hx, 78. 66. Jg, 61. 43. Dq